sigmoid flexure

Then the rivets were cut out similarly at the other point of contrary flexure and the joint opened.
Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3|Various
In the siphon recorder script dots and dashes are represented by curves of opposite flexure.
Heroes of the Telegraph|J. Munro
I may here observe, that sometimes in the sexes a difference is also to be found in the direction or flexure of their antenn.
An Introduction to Entomology: Vol. III (of 4)|William Kirby
Beyond the mid-brain is placed the fore-brain, whose growth is rapidly rendering the cranial flexure imperceptible.
The Works of Francis Maitland Balfour, Volume 1|Francis Maitland Balfour

Great changes have been effected in the head, resulting in a diminution of the cranial flexure.
The Works of Francis Maitland Balfour, Volume 1|Francis Maitland Balfour

British Dictionary definitions for sigmoid flexure

sigmoid flexure

noun

zoology an S-shaped curve, as in the necks of certain birds

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for sigmoid flexure

sigmoid flexure

The S-shaped section of the colon between the pelvic brim and the third sacral segment, continuous with the rectum.sigmoid colon